This is my desired goal: I want to create an app that displays an image and then lets me "draw" on it, simple lines mostly, nothing fancy. After scanning through the Wx docs I found the Wx::ClientDC class which has several methods like "DrawBitmap" and "DrawLine" which looked like exactly what I needed.

However, nothing I've done has come close to working. My code is below. Am I simply making a mistake? Is there a better class I should be using? The code below simply opens a 500 x 500 frame. No rectangle or black of any kind.

use strict;
use Wx qw/wxSOLID/;

package MGV;
use base 'Wx::App';

sub OnInit 
{
  my $self = shift;
    
  my $frame = Wx::Frame->new( undef, -1, 'title', 
    [500,500], [500,500] );
    
  my $dc = Wx::ClientDC->new( $frame );
    
  $dc->SetBrush( Wx::Brush->new( 'black', Wx::wxSOLID ) );
  $dc->DrawRectangle( 100,100, 200,200 );
        
  $frame->Show( 1 );
}

package main;

MGV->new()->MainLoop();
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Update: I think I solved my issue. I changed to using a Wx::PaintDC in a EVT_PAINT:

  $self->EVT_PAINT(
    sub{
      my $dc = Wx::PaintDC->new( $frame );
      $dc->BeginDrawing();
      
        $dc->DrawRectangle( 100,100, 200,200 );
      
      $dc->EndDrawing();
    }
  );
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